1. Field of the Invention
The present invention relates to a gradient estimation apparatus, a gradient estimation method and a gradient estimation program.
2. Related Art
Techniques have been proposed that provide information about the surroundings of a vehicle to a driver for safe driving of the vehicle. There is a technique that calculates the gradient of a road surface, which is a kind of the information about surroundings of a vehicle, based on coordinates of point features of stationary objects photographed by a camera, or based on the width of the spacing between the lane mark lines drawn on the road surface.
For example, a road surface gradient detection apparatus disclosed in JP-A-2008-33781 includes imaging means for imaging a road surface, correlation detection means for detecting the correlation between a plurality of captured images of an arbitrary region captured at different imaging time instants, and gradient detection means for detecting the gradient of the road surface based on the correlation detected by the correlation detection means.